和差模兼载的波纹喇叭自跟踪馈源

本文介绍一个利用HE_(1 1)模及TM_(0 1)模作为自跟踪和模与羞模的波纹喇叭。阐述波纹喇叭和过渡段的波纹壁参数的设计方法。     

时域模拟的电流馈源模型研究

本文分别给出了稳定的无内阻型和内阻型电流馈源模型.前者实现简单,计算精度高.后者克服了前者不适于分析存在基本无耗谐振结构的电磁问题的缺点,而且所需的模拟时间随内阻的适当增加而进一步减少.     

预测反射面天线馈源毁伤效应的混合算法

提出了一种预测反射面天线系统在馈源毁伤状态下辐射特性的混合算法.采用时域有限差分法(FDTD)分析了波导开口辐射器馈源穿孔毁伤时的初级辐射特性,利用物理光学法(PO)和物理绕射理论(PTD)分析了反射面天线的次级辐射特性.并采用非场分裂式完全匹配层(UPML)吸收边界条件、共形网格(Conformalmesh)技术提高计算精度和效率,取得了良好的效果,充分验证了混合算法的有效性.     

介质圆柱的单站微波成像方法

提出一种对介质圆柱实现单站微波成像的方法。该方法通过时域有限差分法进行电磁场正过程的仿真计算,采用整数微分进化策略实现逆过程的寻优计算。分别分析TE模式和TM模式的近场散射信号得到介质成像目标在电磁波传播方向上尺寸大小的估计,并以此为依据,确定成像目标的尺寸范围,从而确定逆过程的寻优区间。该方法无需像传统成像方法围绕成像目标设置多个发射/接收天线以获取成像信息,从而大大减少了成像的必要条件。采用该方法,在TE模式和TM模式下分别对介质圆柱目标进行仿真成像,获得了良好的效果。     

基于CMAES算法的加速度计多位置新型标定方法

针对粒子群优化算法(PSO)和遗传算法(GA)在加速度计标定优化后期出现早熟、陷入局部最优,以及在设计与应用过程中存在的缺陷,将自适应协方差矩阵进化策略(CMAES)算法应用于加速度计的快速标定:采用具有不同函数特征的Sphere、Rastrigin和Rosen三个基准函数对比测试CMAES算法的总体性能;以模观测标定方法为基础建立加速度计标定模型,选取加速度计的24个位置进行仿真观测.实验结果表明:CMAES算法在收敛速度、收敛精度、全局搜索等方面性能优异,将加速度计的标定精度提升了12个数量级,为其它算法标定加速度计奠定了良好基础,对位移系统测量研究具有重要意义.     

A rectangular corrugated feed horn

This paper presents typical results of measurements made on a square corrugated horn and also one with a small rectangular aperture that was designed to generate an elliptical beam for either of two orthogonally polarized signals.     

Simplified high-performance dual-band feed comprising a dual-depth corrugated launcher and a conventional corrugated horn

The design of a corrugated feed is presented which has a simplified configuration in comparison to a feed with dual-depth corrugations over its full length. It exhibits excellent electrical performance which is compatible with the requirements for frequency reuse application in satellite communication antennas. The feed consists of a short dual-depth corrugated launcher and a conventional corrugated horn. Important electrical characteristics of such a feed designated for operation in the standard bands of 4 and 6 GHz satellite communication links are presented.     

An analysis of a two-dimensional dielectric covered corrugated antenna feed horn

The effect of placing a dielectric slab over a90degcorrugated feed horn is investigated. The feed horn is normally a circular waveguide with concentric grooves in the aperture plane. Here we simulate the90degfeed horn with a two-dimensional configuration which is a parallel-plate waveguidewith adjacent notches. The equivalence principle and modal analysis are used to formulate integral equations which are solved numerically by the method of moments. Numerical results for the input admittance are obtained with and without the corrugation and with and without the dielectric slab cover.     

Design and analysis of a multimode feed horn for a monopulse feed

The design of a multimode feed horn for use in a monopulse feed system is summarized. Both amplitude and phase patterns have been obtained and compared with measurements. The far-field amplitude and phase patterns are computed in consideration of achieving the desired aperture distributions for the sum and difference beams. The phase center of the horn is discussed in relation to the multimode excitation and frequency dispersion. It is shown that the phase center location moves as the mode content changes, and proper adjustment of the mode content will result in design optimization. Some tradeoff curves are also presented for design optimization     

星载Ka频段波束赋形波纹喇叭天线设计

提出一种具有稀疏波纹结构的波纹喇叭天线,仅有2圈波纹,结构简单,易于设计加工。通过对天线参数的设计优化,可实现平顶波束赋形,在±40°的波束赋形范围内增益优于5 dBi,天线副瓣优于-30 dB,整个工作频段内驻波比(VSWR)优于1.8,适用于高轨卫星星间通信。通过对一个Ka频段样品的加工、测试和结果比对,验证了该设计方案的正确性。     

Design realization and measurements of a high performance wide-band corrugated horn

We report on the design and realization of horn antennas required to achieve high performances with respect both to the return loss and the cross polarization level over a wide band.     

太赫兹超高斯波纹喇叭天线设计

设计了一种新型太赫兹(THz)超高斯波纹喇叭天线。它由正弦曲线部分和线性平行部分组成,可同时激励起HE11和HE12两种模式。该天线工作的中心频点为0.34 THz,带宽大于40 GHz。在本文设计中,高斯基模的能量耦合效率可提高到99.8%。同时具有-37 dB的旁瓣电平和-50 dB的交叉极化特性。仿真和实测结果也表明此天线的优良性能,可以看出仿真结果与实测结果非常吻合。     

Paraboloidal reflector offset fed with a corrugated conical horn

A paraboloidal reflector, offset fed with a corrugated conical horn, has been examined as a possible antenna for use in millimeter wave communications systems when minimization of interference is an important consideration. Low far-out and back-lobe radiation were primary objectives. Experimentally obtained data, representative of performance at 37 GHz, is presented. When appropriately shielded to limit spillover, levels more than 75 dB below the main beam maximum have been obtained in the far-out and back-lobe regions.     

Investigation of a 90° corrugated horn

Wide-angle corrugated horns have found important practical applications as feeds for front-fed reflector antennas when low levels of crosspolarisation are required. A theoretical study has been carried out on the 90° corrugated horn for a structure possessing an 'arbitrary, but finite, number of corrugations. Computed and measured results are shown to be in good agreement for a horn possessing three annular slots.     

a broad-band constant beamwidth corrugated rectangular horn

Using aperture field theory to predict the far-field radiation from a rectangular horn, a horn with substantially constantE- andH-plane beamwidths of17degand10degrespectively, is designed to operate over a 2.4:1 bandwidth. Assuming a cosine aperture field distribution in both theE- andH-planes of the horn, the general conclusion is first made that an aperture phase error of 0.37 wavelengths at the lowest operating frequency produces the least beamwidth variation (3 dB) over the band. A general design curve showing "constant" beamwidth as a function of horn throat length is produced, furthering the design of such horns with beamwidths in the range approximately9degto27deg. TheE-plane walls of the horn are corrugated, and to cover the bandwidth corrugations are comprised of "T-section" slots which are designed from a simple transmission line model. To realize the specified beamwidths, a compound horn configuration is adopted. Some experimental results obtained from a prototype horn are given.